1. Field of the Invention
The present invention relates to a toe angle detecting apparatus capable of detecting the individual toe angles of each wheel attached to a vehicle.
2. Description of the Related Art
The accurate alignment of vehicle wheels is extremely important for the maintenance of running stability of a vehicle. Therefore, there have been proposed various devices used to measure or check respective states of alignment of the wheels.
As an apparatus for measuring toe angles of wheels, for example, there is known one in which a sensor is brought into contact with side portions of a tire of each wheel so as to detect angular displacements of the wheel with respect to the direction in which each wheel runs forward. However, vehicles as objects to be measured vary in size. Therefore, there are proposed wheel supporting means for supporting the wheels, which can be displaced in the directions of the length and width of a vehicle in order to meet the respective sizes.
However, there is a tendency for positional displacements of the sensor with respect to the wheel supporting means if the apparatus is constructed in this way. As a result, the sensor cannot be reliably brought into contact with each wheel supported by the wheel supporting means, thereby making it unable to detect the toe angle with high accuracy.
On the other hand, any tire varies in shape even when the sensor can be accurately brought into contact with the side portions of the wheel tire. Therefore, the value of the toe angle detected cannot be determined. Even when the tire is temporarily positionally adjusted using the value of the toe angle detected by the sensor, subsequent tire reproducibility is also poor. While the vehicle is running after completion of its adjustment, directional stability characteristics of the vehicle become poor or the angle of a spoke of a steering wheel becomes inappropriate.